Error Message Spammed in Console

[IAmSneak]

The mod doesn't work and this is spammed in console:

[17:10:33] [Thread-52/INFO]: [STDERR]: at java.lang.Thread.run(Unknown Source)
[17:10:33] [Thread-52/INFO]: [STDOUT]: Exception occurred whilst ticking the immersive cursedness thread
[17:10:33] [Thread-52/INFO]: [STDERR]: java.lang.NullPointerException
[17:10:33] [Thread-52/INFO]: [STDERR]: at nl.theepicblock.immersive_cursedness.PlayerManager.lambda$tick$3(PlayerManager.java:63)
[17:10:33] [Thread-52/INFO]: [STDERR]: at java.util.ArrayList.forEach(Unknown Source)
[17:10:33] [Thread-52/INFO]: [STDERR]: at nl.theepicblock.immersive_cursedness.PlayerManager.tick(PlayerManager.java:55)
[17:10:33] [Thread-52/INFO]: [STDERR]: at nl.theepicblock.immersive_cursedness.CursednessServer.lambda$tick$1(CursednessServer.java:60)
[17:10:33] [Thread-52/INFO]: [STDERR]: at java.util.HashMap.forEach(Unknown Source)
[17:10:33] [Thread-52/INFO]: [STDERR]: at nl.theepicblock.immersive_cursedness.CursednessServer.tick(CursednessServer.java:59)
[17:10:33] [Thread-52/INFO]: [STDERR]: at nl.theepicblock.immersive_cursedness.CursednessServer.start(CursednessServer.java:32)
[17:10:33] [Thread-52/INFO]: [STDERR]: at nl.theepicblock.immersive_cursedness.ImmersiveCursedness.lambda$onInitialize$0(ImmersiveCursedness.java:15)

Java version 8
1.16.2
Fabric API 0.22.0-build408